Rheumatoid arthritis (RA) is a kind of chronic autoimmune disease mainly characterized by joint destruction and deformity, which can disable patients. With the morbidity of 0.34% in China, there are nearly five million patients in the whole country, and the percentage of disability reaches up to 93%. The procedure of the onset of the disease is an “initiation—linked immune response” procedure driven by antigens. Immune damage(s) mediated by infection factor(s) and autoimmune response(s) are the basis for the onset and progression of rheumatoid arthritis. Antigen polypeptides are expressed through antigen presenting cells in vivo, and they activate T lymphocyte, which results in the release of cytokines and the increase of production of inflammatory factors, such as immune globulins, chemokines and free radicals, which consequently induce typical pathologic changes of rheumatoid arthritis, including vasculitis, synovium hyperplasia, damage(s) of cartilages and bones.
Currently, there is still no drug which can completely control rheumatoid arthritis. Generally, non-steroidal anti-inflammatory drugs such as Brufen and declofenic acid are used clinically for temporarily relieving symptoms. Disease-modifying anti-rheumatoid drugs, such as methotrexate and leflunomide, are used to extensively inhibit immune responses by suppressing DNA synthesis and thereby inhibit joint inflammation. Therefore, such drugs do not take effect on the initial procedure of the disease onset in the treatment of rheumatoid arthritis, and it is very difficult for them to control the disease completely, which results in the continuous progress of the systemic and joint damages, and disability at last. Moreover, because of the extensive immune suppression of these drugs, there are a lot of side effects, such as myelosuppression and abnormal hepatic functions, and therefore these drugs cannot be administered to many patients.
At present, there is an urgent need for drugs which can take effect on the etiology of rheumatoid arthritis and treat this disease by suppressing the initial procedure of immune responses. Thus after many years of research, the inventors found the non-T cell binding peptides, which can be used for treating rheumatoid arthritis. It proves in our research that the peptides of the present invention can inhibit the recognition to antigens of HLA-DRβ1 molecules and T cells, and thereby inhibit the consequent autoimmune responses. As such, they can prevent and control the onset and development of the disease through the key procedure of the onset of rheumatoid arthritis.